METHOD AND APPARATUS FOR THE APPLICATION OF A CLEANSING OR DISINFECTING FOAM ON A SURFACE

Abstract: In a method for the application of a foam layer to a surface for the purposes of cleansing and/or disinfecting the surface, a concentrated high-pressure foam spray is sprayed at the surface under treatment from a large distance. An even distribution of the foam over the surface is achieved not as a result of the form of the jet, but rather as a result of the impact on the foam jet on the surface. In order to achieve this effect, the foam is sprayed at a distance of at least 4 meters from the surface, under a pressure of at least 4 bars and in a volume of at least 150 liters per minute at the surface being treated.

Description: METHOD AND APPARATUS FOR THE APPLICATION OF A CLEANSING OR DISINFECTING FOAM ON A SURFACE Description The invention relates to a method for the application of a layer of foam to a surface for the purposes of cleansing and/or disinfecting the surface, whereby foam emanating from a spray- head held at a distance from the surface is sprayed in volume and under pressure, whereby a layer of foam which uniformly covers the surface is formed. The invention additionally relates to a foam-spraying apparatus for the implementation of the method, containing a spray-head, a mixing channel equipped with a number of connection-openings to which supply pipes are connected for the supply under pressure of water, compressed air and a foaming product, and a connecting pipe which connects the spray-head to the mixing channel. In industry, it is common practice to use so-called foam- cleaning for the cleansing of floors, walls and machines. This is a procedure for the application of a detergent or other soaking agent, whereby use is made of the cleansing power of the product itself, or of an additive, in order to cover the surfaces to be cleansed with a layer of foam which remains more or less adherent to the surfaces for quite some time. Advantages of this method include, among others, the what longer contact time (foam dries more slowly than liquid product) , the ready visualisation of the work done (it is immediately apparent which surfaces have already been treated and which have not) , and the product-savings (the product adheres to the surface and does not flow immediately towards the floor) . In the application of this procedure, it is usual to make use of a rate of some 40 to 100 liters of foam per minute at the spray-head. In order to cover as large a surface as possible, use is made of a foam-pistol, whereby the spray-hear Is formed by a so-called flat-jet nozzle which converts the foam spray into a flat, wide jet. The optimal results are obtained at a distance of the nozzle from the surface under treatment of some flow is present with a rate of at least 15 liters per minute, and that, in the connecting pipe close to the spray-head, a pressure of at least 4 bars exists and a volume-flow is present with a rate of at least 150 liters per minute. In this way, a sufficiently strong foam jet can be achieved to realise the new impact effect in accordance with the invention. An advantageous embodiment of the foam spraying apparatus according to the invention is characterised in that the apparatus is constructed in such a manner that during its operation, a pressure exists in the supply pipe for the foam products of approximately 6 bars and a volume-flow is present with a rate of about 1.5 liters per minute, and that, in the supply pipe for compressed air, a pressure of at about 8 bars exists, and that, in the supply pipe for water, a pressure of approximately 6 bars exists and a volume-flow is present with a rate of about 30 liters per minute, and that, in the connecting pipe close to the spray-head, a pressure of about 5.5 bars exists and a volume-flow is present with a rate of about 400 liters per minute. A first version of the " invention contains a mobile reservoir with an automated filling installation. This is achieved by means of sucking a vacuum in the tank with the aid of a Ventur- apparatus, whereby the product is sucked out of its original packaging. During the operation of the apparatus, the vacuum pump is automatically rinsed. Another version of the invention is additionally equipped with a level-indication on the tank, containing a float which rises and drops via a straight and a spiral-shaped guide, whereby a needle is made to turn, whereby the level of the reservoir can be read from a scale. Other versions consist of apparatus such as the above- described, but equipped with two or more reservoirs for the same product or possibly for other products, with identical or varying dosage. Another version of the invention is equipped with an automatic dosing system, consisting of two self-regulating (flow) valves - one for the water and one for the product - whereby both volume flows are kept constant and in a fixed relationship with respect to each other. Another version of the invention is equipped with protection against wasting product: a water-controlled valve blocks the supply of compressed air to the reservoir if the water pressure is insufficient. Another version of the invention is equipped with automatic air-bleeding when the tank is at rest. Another version of the invention is equipped with two types of pistol; one for a flat, wide jet and one for a straight jet. Another version of the invention is embodied with a bypass to go around the foam portion so that the system can be used for later rinsing purposes. Another version of the invention is equipped with a selection-tap so that it is possible to operate with varying concentrations of the product. The invention will be elucidated in an exemplary manner hereinafter on the basis of a drawing. To this end: Figure 1 schematically depicts an exemplary embodiment of a foam spraying device, Figure 2 depicts a second exemplary embodiment of a foam spraying device, Figure 3 depicts a portion of the internals of a storage- tank belonging to the foam device. Figure 1 schematically depicts an exemplary embodiment of a foam spraying device 1 which is constructed around a mixing channel 3 formed by a hollow metal cylinder which is connected to a spray-head 7 via a connecting pipe 5. The spray-head 7 has a circular-cylindrical form for the realisation of a concentrated foam spray 9. A connecting mouth 11 for the connection of a (non-depicted) high-pressure water supply is situated at one extreme of the mixing channel 3. Moreover, two further connecting mouths 13, 15 are situated on the mixing channel 3. One of these connecting mouths 13 is connected via a supply pipe 16 to a storage tank 17 within which a foam product 19 is located. A supply pipe 21 for compressed air is connected to the other connecting mouth 15, which supply pipe can be connected with an extreme 23 of a (non-depicted) compressed-air source. The connecting pipe 21 has yet another branch 25 which leads to the supply tank 17, whereby the foam product 19 can be transported under pressure to the mixing channel 3. In addition to the supply tank 17, it is possible to attach other (non-depicted) supply tanks with different foam products, whereby by means of switching the connection of the supply pipe 16 to another supply tank, it is possible to apply these other foam products. Instead of working with supply tanks, it is also possible to connect another dosage-system to the supply pipe 16. The total system can be affixed to a movable trolley and can also be equipped with a compressor for the provision of the compressed air. The spraying can be commenced by means of opening (non-depicted) external water and compressed air taps. As an alternative, taps can be mounted on the apparatus, with which taps the water current and compressed air current can be regulated. For the foam products, it is possible to use alkaline products with a pH value between 0 and 14, acidic foaming cleansing products or a disinfecting foaming product. The advantageous effect commences at a water-pressure value of 5 bars (preferably 10 bars) and a water current of 15 liters per minute (preferably 30 to 35 liters per minute) . The supply tank and connecting mouth for compressed air are hereby connected to a compressed-air pressure of 5 bars (preferably 8 bars) , whereby the foam product also enters the mixing channel at approximately the same pressure level. The volume flow of the foam product obtained in this manner amounts to at least some 0.3 liters per minute (preferably 1.5 to 1.75 liters per minute) . During operation, a foam spray of some 225 liters per minute (preferably 400 liters per minute) at a pressure of at least 4 bars (preferably 5.5 to 6 bars) can be realised at the spray-head with the aforementioned values. A foam layer 31 can be applied to the surface under treatment 29 (which can be, for example, a floor or wall of a workplace, for example, in the food industry) , from a distance 27 from the spray-head 7 to the surface of at least 4 meters (preferably 10 to 16 meters) . The invention can be applied in both mobile and stationary installations and can be implemented for one or more concurrent operators. Figure 2 shows a second exemplary embodiment of a foam spraying device 1* in more detail. Compressed air is supplied be foamed. The output of the collector is coupled via a tap-in point 210 and a foam hose 211 via a blocking tap 212 to a foam- mouth, either for a straight jet or for a V-jet 214 (for a further explanation, see the general description accompanying figure 1) . Figure 3 depicts a portion of the internals of the storage tank 234, for the external read-out of the amount of foam concentrate in the storage tank. An indicator 301 provides an indication of the amount of liquid in the tank. The indicator is mounted on a plate 303 which is placed in such a manner that it can be rotated on a pipe 312 which pipe is additionally used for the supply of compressed air or for the vacuum generation in the storage tank. A float-body 316 is also attached to this pipe 312, which float- body 316 moves upwards and downwards in unison with the level of the liquid. The float-body is connected to the plate 303 via a spiral- shaped rod 7. During the respective rising and falling of the float-body, the spiral-shaped rod pushes (and thereby rotates) the plate 303. In this exemplary embodiment, two floats 217 are coupled to the float-body 316. The compressed air is further let in to and out of the storage tank via an input and output 315, respectively. The product (foam concentrate) is let in to and out of the storage tank via an input/output 314. Another embodiment of the system is equipped with a safety device on the respective filling and emptying hose so that in connected state the tank can only be emptied under low pressure (e.g. 0.5 bars) via the respective filling and emptying hose.

Claims: C L A I M S 1. Method for the application of a layer of foam to a surface for the purposes of cleansing and/or disinfecting the surface, whereby foam emanating from a spray-head held at a distance from the surface is sprayed in volume and under pressure, whereby a layer of foam which uniformly covers the surface is formed, which method is characterised in that the foam is sprayed from such a distance from the surface under treatment, under such a degree of pressure, in such volume, and with a concentrated jet, that as a result of the impact of the jet on the sur f ace, the foam distributes itself evenly over the surface. 2. Method in accordance with claim 1, characterised in that the foam is sprayed at a distance of at least 4 meters from the surface, under a pressure of at least 4 bars and in a volume of at least 150 liters per minute. 3. Method in accordance with claim 2, characterised in that the foam is sprayed at a distance of at least 8 meters from the surface, under a pressure of at least 5 bars and in a volume of at least 350 liters per minute. 4. Method in accordance with claim 3, characterised in that the foam is sprayed at a distance of 10 to 16 meters from the surf< e, under a pressure of between 5.5 and 6 bars and in a volume of between 400 and 600 liters per minute. 5. Apparatus for the implementation of the method in accordance with one of the previous claims, containing a spray- head, a mixing channel equipped with a number of connection- openings to which supply pipes are connected for the supply under pressure of water, compressed air and a foaming product, and a connecting pipe which connects the spray-head to the mixing channel, characterised in that the spray-head has a cylindrical shape and in that the apparatus is constructed in such a manner that during its operation, a pressure exists in the supply pipe for the foam products of at least 5 bars and a volume-flow is present with a rate of at least 0.3 liters per minute, and that, in the supply pipe for compressed air, a pressure of at least 5 bars exists, and that, in the supply pipe for water a pressure of at least 5 bars exists and a volume-flow is present with a rate of at least 15 liters per minute, and that, in the connecting pipe close to the spray-head, a pressure of at least 4 bars exists and a volume-flow is present with a rate of at least 150 liters per minute. 6. Foam spraying device in accordance with claim 5, characterised in that the apparatus is constructed in such a manner that during its operation, a pressure exists in the supply pipe for the foam products of approximately 6 bars and a volume-flow is present with a rate of about 1.5 liters per minute, and that, in the supply pipe for compressed air, a pressure of about 8 bars exists, and that, in the supply pipe for water a pressure of approximately 6 bars exists and a volume-flow is present with a rate of about 30 liters per minute, and that, in the connecting pipe close to the spray- head, a pressure of about 5.5 bars exists and a volume-flow is present with a rate of about 400 liters per minute.

Inventors: DE BLOCK-BURY FRANK PAUL HERMA, MULDER STEVEN, DE BLOCK-BURY, FRANK, PAUL, HERMAN, MULDER, STEVEN
Applicants: BLOCK BURY FRANK PAUL HERMAN D, MULDER STEVEN, DE BLOCK-BURY, FRANK, PAUL, HERMAN, MULDER, STEVEN
Application year: 1994
Main classification: B08B3
IPC codes: B05B7, B08B3, B08B7